Detailed Description

vtkRotationalExtrusionFilter is a modeling filter. It takes polygonal data as input and generates polygonal data on output. The input dataset is swept around the z-axis to create new polygonal primitives. These primitives form a "skirt" or swept surface. For example, sweeping a line results in a cylindrical shell, and sweeping a circle creates a torus.

There are a number of control parameters for this filter. You can control whether the sweep of a 2D object (i.e., polygon or triangle strip) is capped with the generating geometry via the "Capping" instance variable. Also, you can control the angle of rotation, and whether translation along the z-axis is performed along with the rotation. (Translation is useful for creating "springs".) You also can adjust the radius of the generating geometry using the "DeltaRotation" instance variable.

The skirt is generated by locating certain topological features. Free edges (edges of polygons or triangle strips only used by one polygon or triangle strips) generate surfaces. This is true also of lines or polylines. Vertices generate lines.

This filter can be used to model axisymmetric objects like cylinders, bottles, and wine glasses; or translational/rotational symmetric objects like springs or corkscrews.

Warning:

If the object sweeps 360 degrees, radius does not vary, and the object does not translate, capping is not performed. This is because the cap is unnecessary.

Some polygonal objects have no free edges (e.g., sphere). When swept, this will result in two separate surfaces if capping is on, or no surface if capping is off.

Methods invoked by print to print information about the object including superclasses. Typically not called by the user (use Print() instead) but used in the hierarchical print process to combine the output of several classes.